Finding top 10 occurrences in data - sql

Question

I am trying to find the top 10 mentions (#xxxxx) in my twitter data. I have created the initial table twitter.full_text_ts and loaded it with my data.
create table twitter.full_text_ts as
select id, cast(concat(substr(ts,1,10), ' ', substr(ts,12,8)) as timestamp) as ts, lat, lon, tweet
from full_text;
Ive been able to extract the mentions in the tweets by using this query (patterns)
select id, ts, regexp_extract(lower(tweet), '(.*)#user_(\\S{8})([:| ])(.*)',2) as patterns
from twitter.full_text_ts
order by patterns desc
limit 50;
executing this gives me
USER_a3ed4b5a 2010-03-07 03:46:23 fffed220
USER_dc8cfa6f 2010-03-05 18:28:39 fffdabf9
USER_dc8cfa6f 2010-03-05 18:32:55 fffdabf9
USER_915e3f8c 2010-03-07 03:39:09 fffdabf9
and so on...
You can see the fffed220 etc is the extracted patterns.
Now what I would like to do is count the number of times each of these mentions (patterns) occurs and output the top 10. for example fffdabf9 occurs 20 times, fffxxxx occurs 17 times and so on.

Answer 1

The most readable way to do this would be to save your first query into a temporary table, then do a groupby on the temp table:
create table tmp as
--your query
select patterns, count(*) n_mentions
from tmp
group by patterns
order by count(*) desc
limit 10;

Answer 2

with mentions as
(select id, ts,
regexp_extract(lower(tweet), '(.*)#user_(\\S{8})([:| ])(.*)',2) as patterns
from twitter.full_text_ts
order by patterns desc
limit 50)
select patterns, count(*)
from mentions
group by patterns
order by count(*) desc
limit 10;